Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 010605
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
105 AM CDT Mon May 1 2017

.UPDATE...
Issued at 857 PM CDT Sun Apr 30 2017

Scattered thunderstorms were accompanying the cold front, which
at 800 pm, was crossing the Mississippi River. Some of the storms
in southeast Illinois were strong possibly, producing some gusty
winds as they were tracking north-northeast at 55 to 60 mph.
Further west, more widely scattered showers and storms were seen
on radar with brief heavy rainfall associated with those. The
front is expected to push across the forecast area this evening
and move into Indiana at or shortly after midnight. Mild
temperatures ahead of the front will turn colder as winds shift
into the southwest and gust up to 35 mph at times on Monday with
another chance for scattered showers. Drier weather returns
tomorrow night and Tuesday.

&&

.SHORT TERM...(This evening through Monday)
ISSUED AT 307 PM CDT Sun Apr 30 2017

Continued the flash flood watch east of the IL river through 7 am
CDT Monday, and Peoria and Marshall counties were also added. An
area of light to moderate showers spread northward across central IL
today while the thunderstorms were mainly east over IN and western
KY. SPC day1 late morning update shifted the slight risk of severe
storms east of the Wabash river, while still having a marginal risk
of severe storms over central and eastern IL. A band of convection
was developing along the cold front in central MO and ahead of 996
mb surface low pressure in central KS. This line of developing
convection should spread eastward across CWA during this evening
with the cold front. Between a half and 1 inch of rain is possible
during this afternoon and evening, before showers and thunderstorms
chances diminish overnight behind cold front. Lows tonight to range
from mid to upper 40s over western CWA and lower 50s in eastern IL.

A strong 538 dm 500 mb low over south central KS will eject
northeast to near Door County WI by 7 pm Monday. This will keep low
clouds around along with chances of light rain showers especially
north of I-70. Cooler highs in the lower 50s northern CWA and upper
50s in southeast IL. Windy on Monday with sw winds gusting 30-35
mph.

.LONG TERM...(Monday night through Sunday)
ISSUED AT 307 PM CDT Sun Apr 30 2017

12Z models take strong cutoff upper level low ne into eastern Canada
on Tue while weak surface high pressure ridge moves into the MO
valley. After isolated light rain showers over ne CWA Monday
evening, dry wx expected with decreasing clouds and winds overnight
Monday into Tue. Cool lows Monday night of 39-45F with highs Tue
near 60F from I-74 north and upper 60s in southeast IL.

Models still deepen an upper level trof over the central and
southern Plains Wed and into the mid/lower MS river valley on Thu.
Models have trended a bit slower bringing qpf into southern areas
later Tue night and more likely on Wed and Wed night. Still some
question on how far north shower chances get and stayed close to
consensus model solutions with northern CWA drier and higher pops in
southern CWA. Thunderstorms chances still appear to be south of CWA
on Wed afternoon/evening. Highs Wed in the upper 50s to around 60F
with more cloud cover. Highs Thu in the upper 50s/lower 60s with
coolest readings in east central and southeast IL where lingering
chances of light rain showers.

Models differ with handling deepening upper level trof and cutoff
low in the southeast states Thu night and Friday and consensus kept
slight pops in southeast IL along with more clouds and cooler temps
there with lower 60s Fri while mid 60s from I-55 west. Next weekend
looks drier over CWA as weak surface high pressure ridge settles
into area. Highly amplified upper level flow over the country with
cutoff lows and deep trofs over the northeast U.S. and western
states while upper level ridge in between over the Great Plains.
Slowly moderating temps next weekend with highs in the upper 60s Sat
and upper 60s/lower 70s next Sunday which is closer to normal for
early May.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 100 AM CDT Mon May 1 2017

Some variability in the gusty winds still associated with the deep
low to the west. Mainly southerly winds...with PIA and SPI still
with a more westerly component as the cold front from the
occluding system moves through southern IL. Expansive clear slot
pushing mostly VFR cigs through ILX terminals for a few hours. By
mid morning...more showers and MVFR cigs expected to move in with
cyclonic flow as the low slowly drifts to the north and into the
Great Lakes. Winds become SWrly then more westerly and remain
gusty through the forecast.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 7 AM CDT this morning for ILZ029>031-037-
038-041>050-052>057-061>063-066>068-071>073.

Flash Flood Watch through this evening for ILZ051.

&&

$$

UPDATE...Smith
SHORT TERM...07
LONG TERM...07
AVIATION...HJS


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